diff options
| -rw-r--r-- | Documentation/dmaengine/provider.txt | 11 | ||||
| -rw-r--r-- | drivers/dma/virt-dma.c | 19 | ||||
| -rw-r--r-- | drivers/dma/virt-dma.h | 13 | ||||
| -rw-r--r-- | include/linux/dmaengine.h | 8 |
4 files changed, 39 insertions, 12 deletions
diff --git a/Documentation/dmaengine/provider.txt b/Documentation/dmaengine/provider.txt index 05d2280190f1..ca67b0f04c6e 100644 --- a/Documentation/dmaengine/provider.txt +++ b/Documentation/dmaengine/provider.txt @@ -345,11 +345,12 @@ where to put them) that abstracts it away. * DMA_CTRL_ACK - - Undocumented feature - - No one really has an idea of what it's about, besides being - related to reusing the DMA transaction descriptors or having - additional transactions added to it in the async-tx API - - Useless in the case of the slave API + - If set, the transfer can be reused after being completed. + - There is a guarantee the transfer won't be freed until it is acked + by async_tx_ack(). + - As a consequence, if a device driver wants to skip the dma_map_sg() and + dma_unmap_sg() in between 2 transfers, because the DMA'd data wasn't used, + it can resubmit the transfer right after its completion. General Design Notes -------------------- diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c index 6f80432a3f0a..7d2c17d8d30f 100644 --- a/drivers/dma/virt-dma.c +++ b/drivers/dma/virt-dma.c @@ -29,7 +29,7 @@ dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx) spin_lock_irqsave(&vc->lock, flags); cookie = dma_cookie_assign(tx); - list_add_tail(&vd->node, &vc->desc_submitted); + list_move_tail(&vd->node, &vc->desc_submitted); spin_unlock_irqrestore(&vc->lock, flags); dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n", @@ -83,8 +83,10 @@ static void vchan_complete(unsigned long arg) cb_data = vd->tx.callback_param; list_del(&vd->node); - - vc->desc_free(vd); + if (async_tx_test_ack(&vd->tx)) + list_add(&vd->node, &vc->desc_allocated); + else + vc->desc_free(vd); if (cb) cb(cb_data); @@ -96,9 +98,13 @@ void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head) while (!list_empty(head)) { struct virt_dma_desc *vd = list_first_entry(head, struct virt_dma_desc, node); - list_del(&vd->node); - dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd); - vc->desc_free(vd); + if (async_tx_test_ack(&vd->tx)) { + list_move_tail(&vd->node, &vc->desc_allocated); + } else { + dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd); + list_del(&vd->node); + vc->desc_free(vd); + } } } EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list); @@ -108,6 +114,7 @@ void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev) dma_cookie_init(&vc->chan); spin_lock_init(&vc->lock); + INIT_LIST_HEAD(&vc->desc_allocated); INIT_LIST_HEAD(&vc->desc_submitted); INIT_LIST_HEAD(&vc->desc_issued); INIT_LIST_HEAD(&vc->desc_completed); diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h index 181b95267866..189e75dbcb15 100644 --- a/drivers/dma/virt-dma.h +++ b/drivers/dma/virt-dma.h @@ -29,6 +29,7 @@ struct virt_dma_chan { spinlock_t lock; /* protected by vc.lock */ + struct list_head desc_allocated; struct list_head desc_submitted; struct list_head desc_issued; struct list_head desc_completed; @@ -55,11 +56,16 @@ static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan struct virt_dma_desc *vd, unsigned long tx_flags) { extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *); + unsigned long flags; dma_async_tx_descriptor_init(&vd->tx, &vc->chan); vd->tx.flags = tx_flags; vd->tx.tx_submit = vchan_tx_submit; + spin_lock_irqsave(&vc->lock, flags); + list_add_tail(&vd->node, &vc->desc_allocated); + spin_unlock_irqrestore(&vc->lock, flags); + return &vd->tx; } @@ -122,7 +128,8 @@ static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) } /** - * vchan_get_all_descriptors - obtain all submitted and issued descriptors + * vchan_get_all_descriptors - obtain all allocated, submitted and issued + * descriptors * vc: virtual channel to get descriptors from * head: list of descriptors found * @@ -134,6 +141,7 @@ static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, struct list_head *head) { + list_splice_tail_init(&vc->desc_allocated, head); list_splice_tail_init(&vc->desc_submitted, head); list_splice_tail_init(&vc->desc_issued, head); list_splice_tail_init(&vc->desc_completed, head); @@ -141,11 +149,14 @@ static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) { + struct virt_dma_desc *vd; unsigned long flags; LIST_HEAD(head); spin_lock_irqsave(&vc->lock, flags); vchan_get_all_descriptors(vc, &head); + list_for_each_entry(vd, &head, node) + async_tx_clear_ack(&vd->tx); spin_unlock_irqrestore(&vc->lock, flags); vchan_dma_desc_free_list(vc, &head); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 19face3168b4..5d99229c2f95 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -123,10 +123,18 @@ enum dma_transfer_direction { * chunk and before first src/dst address for next chunk. * Ignored for dst(assumed 0), if dst_inc is true and dst_sgl is false. * Ignored for src(assumed 0), if src_inc is true and src_sgl is false. + * @dst_icg: Number of bytes to jump after last dst address of this + * chunk and before the first dst address for next chunk. + * Ignored if dst_inc is true and dst_sgl is false. + * @src_icg: Number of bytes to jump after last src address of this + * chunk and before the first src address for next chunk. + * Ignored if src_inc is true and src_sgl is false. */ struct data_chunk { size_t size; size_t icg; + size_t dst_icg; + size_t src_icg; }; /** |